Calculate current per phase from 3-phase power, line voltage and power factor, or split total current evenly across 1, 2 or 3 phases.
- All Physics Calculators
- Line to Phase Current Calculator
- 3 Phase Current Calculator
- Single Phase Power Calculator
Current Per Phase Formula
The current per phase depends on which input method you use. For a balanced 3-phase load, the calculator uses real power, line-to-line voltage, and power factor. If you already know the total current across phases, it divides that total by the number of phases.
I = \frac{P}{\sqrt{3} \times V_{LL} \times PF}- I = current per phase, in amperes (A)
- P = real load power, in watts (W)
- VLL = line-to-line voltage, in volts (V)
- PF = power factor, from 0 to 1
I_{phase} = \frac{I_{total}}{N}- Iphase = current per phase, in amperes (A)
- Itotal = total current summed across all phases, in amperes (A)
- N = number of phases
From Power (3-phase): Use this mode when you know the load power, line voltage, and power factor. The calculator converts the entered power to watts if needed, then applies the balanced 3-phase current formula.
Split Total Current: Use this mode when you already have a total current value and want to divide it evenly across a chosen number of phases. This assumes the load is balanced between phases.
Typical 3-Phase Voltage and Power Factor Values
These values can help you choose reasonable inputs when exact equipment data is not available.
| System or region type | Common line-to-line voltage | Notes |
|---|---|---|
| Small commercial 3-phase | 208 V | Common in North American commercial buildings |
| Industrial or commercial | 400 V or 415 V | Common in many IEC-based electrical systems |
| Industrial 3-phase | 480 V | Common for motors, drives, and building equipment |
| Large industrial | 600 V | Used in some industrial distribution systems |
| Load type | Typical power factor | Use when |
|---|---|---|
| Resistive load | 1.00 | Heaters or mostly resistive equipment |
| Modern drive or corrected load | 0.95 | VFDs, corrected equipment, or efficient systems |
| Mixed load | 0.85 | General estimate when loads include motors and other equipment |
| Motor load | 0.80 | Typical induction motor estimate |
Current Per Phase Examples
Example 1: Find current per phase from 3-phase power
You have a 50 kW balanced 3-phase load on a 400 V system with a power factor of 0.85.
I = \frac{50000}{\sqrt{3} \times 400 \times 0.85}I = 84.9\text{ A}The current per phase is about 84.9 A.
Example 2: Split total current across phases
You have a total current of 90 A across 3 phases and want the current per phase.
I_{phase} = \frac{90}{3}I_{phase} = 30\text{ A}The current per phase is 30 A.
Current Per Phase FAQ
Is current per phase the same as line current?
In a balanced 3-phase system, the current per phase is usually the same value as the line current when using the standard 3-phase power formula with line-to-line voltage. For an unbalanced system, each phase can carry a different current, so a single current-per-phase result is only an average or estimate.
Why does power factor change the current?
Power factor shows how effectively the electrical power is being used. A lower power factor means more current is needed to deliver the same real power. For example, a 50 kW load at 0.80 power factor draws more current than a 50 kW load at 0.95 power factor on the same voltage.
Can you use this for single-phase current?
The power-based mode is for balanced 3-phase loads because it uses the √3 factor and line-to-line voltage. For simple single-phase current from power, the basic formula is I = P / (V × PF). The split-current mode can still divide a known total current by 1 phase, 2 phases, or 3 phases if that is the calculation you need.
